This invention relates to hay harvesting and conditioning machines, such as mower-conditioners and wind-rowers, of the type having a mobile frame to which is mounted a laterally elongated header having hay cutting apparatus and a pair of laterally disposed crop conditioning rolls mounted thereon and, more particularly, to apparatus for automatically opening the conditioning rolls when the header is raised to the transport position.
Previous automatic conditioning roll opening devices for hay conditioners are disclosed in Johnston, et al. U.S. Pat. No. 3,397,520 and Peacock, et al. U.S. Pat. No. 3,672,135. In these devices, the conditioning rolls are automatically raised by a linkage when the header is raised. This system is effective for clearing the rolls when they become clogged with excess crop or other debris during operation. However, in the Johnston, et al. patent, the carrying wheels were pivoted on the header frame, and in the Peacock, et al. patent the header was pivotally mounted on the frame and thus the header had no lateral floatation. In the present invention, the crop harvesting header is mounted by a three point suspension from a wheeled carrying frame in a four bar linkage arrangement providing lateral floatation as well as advantageous movements of the header relative to the frame, as may be seen in copending application Ser. No. 914,321. However, the very flexibility of the mounting in the operating position can lead to difficulties in the transport position with the header bouncing vertically and swinging laterally relative to the frame, particularly when the floatation springs are not adjusted equally or in side hill operation.